CSIRO Agriculture & Food, St Lucia, QLD, Australia.
School of Animal Studies, The University of Queensland, Gatton, QLD, Australia.
PLoS One. 2023 Jan 26;18(1):e0279398. doi: 10.1371/journal.pone.0279398. eCollection 2023.
Worldwide, most beef breeding herds are naturally mated. As such, the ability to identify and select fertile bulls is critically important for both productivity and genetic improvement. Here, we collected ten fertility-related phenotypes for 6,063 bulls from six tropically adapted breeds. Phenotypes were comprised of four bull conformation traits and six traits directly related to the quality of the bull's semen. We also generated high-density DNA genotypes for all the animals. In total, 680,758 single nucleotide polymorphism (SNP) genotypes were analyzed. The genomic correlation of the same trait observed in different breeds was positive for scrotal circumference and sheath score on most breed comparisons, but close to zero for the percentage of normal sperm, suggesting a divergent genetic background for this trait. We confirmed the importance of a breed being present in the reference population to the generation of accurate genomic estimated breeding values (GEBV) in an across-breed validation scenario. Average GEBV accuracies varied from 0.19 to 0.44 when the breed was not included in the reference population. The range improved to 0.28 to 0.59 when the breed was in the reference population. Variants associated with the gene HDAC4, six genes from the spermatogenesis-associated (SPATA) family of proteins, and 29 transcription factors were identified as candidate genes. Collectively these results enable very early in-life selection for bull fertility traits, supporting genetic improvement strategies currently taking place within tropical beef production systems. This study also improves our understanding of the molecular basis of male fertility in mammals.
在全球范围内，大多数肉牛繁殖群体都是自然交配的。因此，识别和选择有生育能力的公牛对于提高生产力和遗传改良至关重要。在这里，我们收集了来自六个热带适应性品种的 6063 头公牛的十个与生育力相关的表型。表型包括四个公牛体型特征和六个与公牛精液质量直接相关的特征。我们还为所有动物生成了高密度 DNA 基因型。总共分析了 680758 个单核苷酸多态性（SNP）基因型。在大多数品种比较中，阴囊周长和鞘评分的同一性状的基因组相关性为正，但与正常精子百分比的相关性接近零，这表明该性状的遗传背景存在分歧。我们证实了在跨品种验证场景中，参考群体中存在品种对于生成准确的基因组估计育种值（GEBV）的重要性。当品种不包含在参考群体中时，平均 GEBV 准确性从 0.19 到 0.44 不等。当品种包含在参考群体中时，范围提高到 0.28 到 0.59。与基因 HDAC4、生精相关（SPATA）蛋白家族的六个基因和 29 个转录因子相关的变体被确定为候选基因。这些结果共同实现了对公牛生育力性状的早期选择，支持了目前在热带牛肉生产系统中进行的遗传改良策略。本研究还提高了我们对哺乳动物雄性生育力分子基础的理解。
